This invention relates to a scroll compressor having a non-orbiting scroll with load bearing ribs.
Modem refrigerant compressors are often mounted within a sealed container. In these compressors, the pump unit for compressing the refrigerant is positioned at one end, and a motor for driving the pump unit is positioned at another end. Often the suction pressure refrigerant is allowed to circulate over the motor, cooling the motor. In such compressors, it becomes necessary to separate a suction pressure chamber from a discharge pressure chamber.
One popular type of modern compressor is a scroll compressor. A scroll compressor includes a pair of scroll members each having a base and a generally spiral wrap extending from the base. The wraps of the two scroll members interfit to define compression chambers. One of the scroll members is driven to orbit relative to the other, and during this orbital movement, the compression chambers decrease in volume.
In traditional scroll compressors, the non-orbiting scroll does not seal against the compressor housing. Instead, a separate separator plate is positioned typically outwardly of the base of the non-orbiting scroll to separate the housing into the suction and discharge pressure chambers. Most typically, a discharge pressure chamber is formed above the separator plate, and the area below the separator plate is at suction pressure.
More recently, it has been proposed to incorporate the separator function into the base of the non-orbiting scroll. In such compressors, the base of the non-orbiting scroll is sealed to the housing. Thus, there is the discharge pressure chamber on one side of the base of the non-orbiting scroll and the suction pressure chamber on the other.
In such compressors, compressed refrigerant often reaches relatively high pressures. With the above discussed recent scroll compressor improvements, this high pressure may cause the scroll base to deform toward the suction side of the compressor. This deformation is undesirable.
One proposed design employs ribs extending radially from the center of scroll base across a limited portion of the base. This design may not offer sufficient support to the base. Moreover, the design only offers support along a radial path from the base""s center.
A need therefore exists for a scroll base having greater support against deflection and deformation.
In a disclosed embodiment of this invention, a scroll compressor has an orbiting scroll member and a non-orbiting scroll member. The non-orbiting scroll is utilized to separate a housing containing both scroll members into suction and discharge pressure chambers. Preferably, the non-orbiting scroll has an outer peripheral surface sealed to a inner peripheral surface of the housing defining the suction and discharge pressure chambers. Other ways of sealing the non-orbiting scroll to the housing may be used. To limit deflection of the non-orbiting scroll, ribs are formed on the outer face of the base of the scroll member. The ribs preferably offer support along a radial and non-radial path from the center and may extend across the entire scroll member.
The ribs preferably extend from a center portion of the non-orbiting scroll member to the periphery of the member. The extension of ribs to the periphery permits the distribution of load caused by the pressure differential between the discharge pressure chamber and the suction pressure chamber across the entire member. In addition, a rib is preferably formed along the periphery to provide further support. This peripheral rib intersects the ribs extending from the center portion. The radially extending ribs meet in the center portion and connect to a boss of the non-orbiting scroll member. The non-orbiting scroll member typically has a circular outer peripheral shape.
The ribs preferably form a radial design extending from the center portion of the base. In addition, the invention envisions the use of ribs so as to distribute loads not only radially but in a non-radial fashion across the non-orbiting scroll member. Alternate rib embodiments crisscross and intersect each other to distribute load across other portions of the non-orbiting scroll member. Some rib embodiments intersect at perpendicular angles.
The present invention accordingly permits the non-orbiting member to be supported by ribbing and avoid deflections and deformities caused by their absence, thereby providing greater support to the non-orbiting member.